Silencer



July 18, 1939. w. L. MANNING SILENCER Filed July 1, 1938 4 Sheets-Sheet1 July 18, 1939. w. L. MANNING SILENCER Filed July 1, 1938 4Sheets-Sheet 2 /mv b@ J J a. w

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July 18, 1939.

W. L. MANNING SILENCER I 4 Sheets-Sheet 4 Filed July 1, 1938 o 0 ya o oM n0 m g 000 m n M y 0 Z w 4/ 00 0 m 3 five/z @7212 A @m Pa e! in, 18,1939 2,166,417

UNITED STATES PATENT OFFICE v BIIENOER.

wuun 1. Manning, Madison, Wis., assigno'r to Burgess Battery Company,Chicago, Ill., a cor= poration of Wisconsin I Application July 1, 1938,Serial No. 216,856 15 Claims. (Cl. 181-54) The present invention relatesto silencers, and Fig. 7 is a longitudinal sectional view of afurparticularly to silencers for quieting the exhausts ther modificationof the invention;

and intakes of internal combustion engines. Fig. 8 is a longitudinalview of a further modifi- It is the object of the invention to provide acation of the invention; silencer of simple design and economicalconstruc- Fig. 9 is a broken longitudinal sectional view of 5 tion whichhas high silencing efliciency throughthe modification shown in Fig. 8;out the frequency range usually encountered in Fig. 10 is a transversesectional view along line internal combustion engines, and whichinterill-l0 of Fig. 9; poses but slight restriction upon the flow there-Figs. 11 and 13 are longitudinal sectional views 10 through. of furthermodifications of the invention; .and 10 Briefly, the invention providesa silencer of the Figs. 12 and 14 are transverse sectional viewsretroverted passage type having conduits for the along line i2l2 of Fig.11 and line l4-l4 of first and last passages but not for the'intermedi-Fig. 13 respectively. ate passage, the sounds and gases employing theThe silencer of Figs. 1, 2 and 3 comprises an 5 space within thesilencer casing for their passage imperforate outer shell or casing I0,closed at its 15 between the first and last passages. The silencer endsby end walls I l and i2. Said end walls have also provides means wherebythe gases at some substantially central openings i3 and I l therein,point in their passage therethrough are caused to and inlet tube I5 andoutlet tube It are mounted impinge upon a surface interposed directlyacross on said openings respectively. A. number of their path to breakupthe high pressure slugs, the spaced transverse bulkheads or partitionsl1, I8, 20 gases, however, being free to flow laterally of such Hand 20are provided within the interior of casmeans with substantially norestriction, with the ing it to form a number of compartments or resultthat but little restriction is caused by said chambers 2i, 22, 23, 24and25. Partition il' has means. eccentric openings 26 and 21 therein,said open- A silencer of such construction is particularly ings havingrelatively short, open-ended, per- 5 well adapted for silencing engineexhausts where forated or ioraminous tubes 28 and 29 mounted at a shorttail pipe, or no tail pipe, is employed. In one end in said openings andextending inwardly exhaust silencers which do not employ bellies atoward partition IS, the inward open ends of tubes pipe of appreciablelength is required to be con- 28 and 29 being spaced from partition I.The I 30 nected between the outlet of the silencer and the portion ofpartitieni'l whi is pp the inlet 30 atmosphere, this pipe being called atail pipe and opening I: is imperforate. serving to load the silencer.This loading has Partitions I8, l9 and 20 have central openings beenfound to be necessary in order that the therein and an Opentube 39,Perforated silencer function with effectiveness. In someapthroughout itslength, is mounted at one end upon plicatlons, because of spacerequirements, the use end wall I! and extends throu h ch m 35 of a tailpipe of the requisite length is impracand 25 and the said openings'inpartitions I8, I9 ticable. The silencer of this invention is entirelyand 20 a d pa ia y u h c a er 22- toward efiective without a tailpipeand hence is especially partition ll. the p of tube 30 being pa usefulin the situations described. However, its m said partition ll. Tube 30is in ali n n 40 application is not limited to such situations. and i aconnected to t e t et pe in 40 it may be used in all the usualapplications for T es 28 and 29, extending from partition intosilencers. chamber 22, and tube 30 extending from partition In thedrawings: i8 into the same chamber are coextensive within Fig. l is alongitudinal view of on form of th compartment 22 for a. considerableproportion of silencer of this invention; the length of the saidchamber. The tubes may 45 Fig. 2 is a transverse sectional view alongline be in contact with one another as shown and may 2-4 of Flgs.1 and3; be fastened together, as by welding, to provide Fig. 3 is a brokenlongitudinal sectional view increased strength and rigidity. The chamber25 along line 3-4 of Fig. 2; surrounding tube 30 is filled with asuitable sound- Fig. 4 is a longitudinal view of a different formabsorbing and gas-pressure-absorbing material, 50 of the invention; suchas steel wool or other metallic wool, exfoli- Fig. 5 is a transversesectional view along line ated vermiculite, asbestos fibers, rock wool,pumice 5--5 of Figs. 4 and 6; and other loose ceramic aggregates, oraggregates Fig. 6 is a broken longitudinal sectional view bondedtogether with a suitable adhesive so as to along line H of Fig. 5;provide intercommunicating pores and channels 55 .the perforationsandthe open end thereof.

within the material. The perforations or openings in the tubes 26 and 30of this form of the invention, as well as the perforations or openingsin the tubes of the modifications hereinafter to be described, may beother than round and may be larger or smaller than shown.

In operating the silencer as an exhaust silencer, tube I5. is connectedto the exhaust pipe of the internal combustion engine and the exhaustgases enter the said tube, as indicated by the arrow in Fig. 3, andimpinge against the imperforate central portion of partition H. Theslugs of gas under high pressure are broken by this impingement and thegas is free to expand and travel laterally within chamber 26, which itdoes and passes out of the said chamber through openings 25 and 21, andproceeds into perforated tubes 28 and 29. The gas passes from tubes 28and 29 into chamber 22, and from said chamber into tube 30. A portion ofthe gas passes directly laterally from tubes 28 and 29 and into tube 30through the perforations of the said tubes. Another portion passesthrough the said perforations in tubes 28 and 29 expands into the volumeof chamber 22 with a resulting decrease of pressure. They then pass moreslowly intowtube 30 through A further portion travels as a stream out ofthe open ends of tubes 28 and 29, where it impinges against partitionl8, reverses its direction ,and travels forwardly in the form of aconverging stream to the forward end of chamber 22 where it impingesagainst partition l1 and again reverses its direction and passes intothe open end of tube 30. The gases proceed through tube 30 and out ofthe silencer through the outlet opening l4 thereof, as indicated by thearrow in Fig. 3. In their impingements against the surfaces ofpartitions I! and 18 the high, pressure slugs of gas are broken andtheir intensity is reduced. The enclosed volumes'of chambers 23 and 24are connected to tube 30 by the perforations of the latter andconstitute resonating chambers, which exert a silencing action upon theexhaust noises. The sound-absorbing material 3| in chamber 25 alsoexerts a silencing action.

The silencer described heretofore produces a highly effective silencingaction, so that a relatively small silencer is required in comparisonwith silencers of different types. It is effective over the entire rangeof frequencies usually encountered in internal combustion engines, andpossesses the, property of substantially eliminating the slugs of highpressure gas which are only partially suppressed in many other types ofsilencer and which resulth'i sharp cracks of noise,

especially when the engihe is performing under relatively heavy loads.The silencer does not require a tail pipe to give it eflectiveness.

The modification shown in Figs. 4, 5 and 6 comprises an imperforatecasing 35 having end walls 36 and 37, end wall 38 having an inlet open-48 and 50, the-central portion thereof, which is directly opposed to theentrance opening 38, being solid. Perforated tubes 5| and 52 are mountedat one end in openings 49 and-50 respectively and extend inwardly ofchamber 46 a distance short of partition 43. Partitions 43 and 44 areprovided with central openings. and a perforated tube 53 is mounted atone end within. flange 40 and extends forwardly through partitions 44and 43 and into chamber 48 a distance short of the forward wall, 42thereof. Tubes 5| and 52 are coextensive with tube 53 for a portion oftheir lengths within chamber 46, and the tubes may be in contact withone another as shown and may. be joined together as described heretoforein connection with the construction of Figs. 1, 2 and 3.

The operation of this silencer is similar to that of Figs. 1, 2 and 3.The construction is more rugged and adapted for more severe service. Forexample, sleeve members 54 are provided in the different partitions forthe support of the tubes. The silencer of Figs. 1, 2 and 3 is ingeneral, to be used where a smaller silencer is permissible and (wherethe conditions of service are such that there is less vibration,shaking, etc.

The silencer of Fig. 7 comprises a casing 55 having end walls 56 and 51and partitions 58 and59, the latter dividing the interior of thecasinginto chambers 60, 6t and 62. The end walls have central openings63 and 64 therein and an inlet tube connection 65 and an outlet tubeconnection 66 mounted in said openings respectively.

A relatively long perforated tube 61 is mounted at one end within theopening of end wall 56 and passes through a central opening in partition58 and extends into chamber 6l stopping some distance short of partition59. Partition 59 has two eccentric openings therein, and perforatedtubes 88 and 69 mounted at one end within said openings and extendforwardly to within a short distance of partition 58.

In this construction the exhaust gases enter the silencerthrough-entrance opening 63, as indicated by the arrow, and firstencounter the silencing effect of resonating chamber 60. They ing 38therein, and end wall 37 having an outlet opening 39 therein, aninwardly extending flange 40 being provided at the opening to. Thesilencer is adapted particularly for connection to flanged pipes,and forthis purpose the endwalls have stud bolts 4| threaded into them andadapted to have cooperating flanges fitted over them and fastened bysuitable nuts against the surfaces of the said end walls. a

The interior of casing 35 is provided with spaced, transverse partitions42, 43 and 44 which divide the easing into chambers 45, 46, 41 and 48.Partition 42 is provided with eccentric p ng 6! where some of them passlaterally through the openings of tube 61 and tubes 68 and 69 into thelatter tubes, and others emerge longitudinally from the end of tube 81and impinge upon the solid portion of partition 59, where the slugs ofhigh pressure gas are broken as described heretofore, and the gasreverses its direction and flows forwardly-in chamber 6! and passesthrough the perforations of tubes 68 and 69 into said tubes, some of ittraversing the entire length of chamber 6!! and reversing its directionat the forward end thereof and entering tubes 68 and 69 through the endsthereof. Slugs of high pressure gas passing forwardly in chamber Siimpinge against the surface of partition 53, and, likewise, anyremaining slugs passing rearwardly within tubes 58 and 68 impingeagainst the solid surface of rearward end wall 5'! and are again broken.At any of these impingements the gas slugs are free to expand andtravellaterally so that a minimum of back pressure is created, but atthe same time the slug-breaking action is effective, with the resultthat the gases emerge at spaced apart laterally, although they may be in76 contact with one another as they are in the modifications describedheretofore.

In the modification shown in Figs. 8, 9 and 10 the gas passes throughtwo stages in each of which it undergoes two complete reversals ofdirection. This modification comprises an imperforate casing I0 havingend walls II and I2, the end walls having openings I3 and I4 thereinrespectively and having inlet tube I5 and outlet tube I6 in saidopenings. An imperforate transverse partition II is locatedsubstantially centrally of the casing I0 and subdivides the casing intotwo chambers I8 and I9. Tubes I5 and I6 extend into chambers I8 and I9toward transverse wall 11, the interior ends of said tube being spaced asubstantial distance from said wall. The portion of the tubes I5 and I6located within the said chambers are perforated, or foraminous. rated,open ended tubes are arranged longitudinally within casing I0 and aboutcentral tubes I5 and I6, tubes 80 passing through corresponding openingsin transverse wall II. The tubes 80 extend outwardly a substantialdistance in both directions beyond the inner ends of tube I5 and I6. Ator adjacent the left ends of tubes 80, as seen in Fig. 9, they areattached to the inlet tube I5, as by means of welding, and at or nearthe other ends they are fastened to outlet tube I8 by means of anannular plate or spider 8| having openings therein to accommodate thetubes. Outlet tube IB is of slightly reduced diameter in comparison withtube I5 for the purpose of increasing somewhat the loading effect ofthis tube upon the silencer.

In this construction there are no resonating chambers such as are foundin the constructions described heretofore. The gases enter chamber I8through tube I5, as indicated by the arrow, where they pass from tube I5to tubes 80 by an action similar to that described in connection withFig. '7 during which they undergo a double reversal of direction. Theythen pass through tubes 80 into chamber I9 where they pass into outlettube IS in the manner described in connection with Figs. 1, 2 and 3,again undergoing a double reversal of direction. In this constructionthe absence of resonating chambers is compensated by the presence of thestage in which the gases undergo the second double reversal ofdirection. The fact that exit tube I6 is of slightly smaller diameterthan inlet tube I5 results in an increased silencing effect.

The modification shown in Figs. 11 and 12'comprises an imperforatecasing having end walls an eccentric opening therein and aperforatedtube 96 is mounted at one end within said, opening and extendstoward the opposite end of the silencer. In a similar manner bulkhead 91is mounted adjacent the otherendsof the silencer and has an eccentricopening therein, in which is mounted a perforated tube 98 which"extends"toward bulkhead The silencer is r symhret rical construction and eitherend may be used as the entrance. When tube 93 is the entrance tube I theexhaustgases impingeagainst the solid portion of bulkhead. 95 and'expandand, travel lat-'1 erally and' then pass into tube' 9'6.' The passagefrom tube 96 to tube 98 is in themanner described heretofore inconnection with the" earlier described modifications, some of the gasesim Four perfopinging against bulkhead 91. After emerging from tube 98some of them also impinge against end wall", after which they are freeto expand laterally and pass out of the silencer through outlet tube 94.

In the modification illustrated in Figs. l3 and 14 one of the passageswithin the directionreversing chamber is in the form of an annularconduit instead of a tube. The silencer comprises the imperforatecasingI having end walls IN and I02, end wall III having inlet connection I03,and end wall I02 having outlet connection I04 mounted therein. Theperforated inlet tube I05 for the silencer is mounted in the opening ofinlet end wall III and extends toward the oppositeend'of the' casing. Aperforated intermediate cylindrical shell III is spaced interiorly fromcasing I00 and extends from a point spaced from the rearward end of tube"5 forwardly to a point spaced from the forward end wall iii. Therearward end pf intermediate shell I is closed by an imperforate plateIN. The intermediate shell is mounted adjacent its rearward end by meansof brackets III! which are supported by the casing I", and is supportednear its forward end by brackets II! which extend between it and theinlet tube I05. The space between intermediate shell I98 and casing I"forms an annular outlet conduit III The plate IIII forms a partitionsubdividing the casing into the direction-reversing chamber III and thechamber H2 at the rearward end of the cas'ing,"chamber III serving toconnect outlet passage I III to the outlet connection III of thesilencer.

In this construction the gases enter tube I05 as indicated by the arrow,and some of them pass laterally through the openings of tube I05 andintermediate shell I 06 into the outletconduit III), while otherscontinue as a stream through the inlet tube and impinge against plateI01, where their direction is reversed and they travel forwardly throughthe interior of the direction-reversing chamber ,1 III and impingeagainst forward end wall IIiI, when their direction is again reversedand they pass rearwardly .through outlet conduit H0 and into the chamberIII at the outlet end of the, silencenahdthence into the outletconnection I. In this construction the direction of the gases maybereversed from that described.

the openings in the walls of the perforated tubes may be varied'withinlimits-of between approxi-, and 10% of the area or the-said mately 0.01%walls. Within this range theop'ening area may be 50 In the silencers ofthis inventionthear'ea of varied to secure the best performance for theparticular application. In general, the attenua-' tion becomes shiftedto a lower frequency range as the proportion of open areafbe'comes less.If

the area of openings is outside the range stated the silencing isnotefiectivethroug hout the frequency range formance.

,requiredff oi" satisfactory 'per- I It is understoodthat"the'ihveiitiomishot lim ited'to the constructions""specificallyset-forth but that variations maybemade without depart'- ing from thescope of-th'e invention; Thei'o'uter;

casing need notbe cylindrical {as shown, but may be ovalo'r angular intransverse-shape. '.Soundabsorbing and. gasi-pressuretabsorbing,material may be placed in chambers otherrthan chamber 25 f Fi onmayw e-ip ed in add tiona j chambers, and it ,may-beplaqed in chamber ll,

arranged in juxtaposed relation within may be varied to suit theindividual application of the silencer. The number, size, length andlateral arrangement of the tubes within the easing may be varied. Thoseportions of the tubes which pass through the resonating chambers ofFigs. 1 to 7 inclusive may have one or more larger openings therein formaking connection to the interior of the chambers, instead of beingforaminous as describedherein.

This application is a continuation in part of my co-pending applicationSerial No. 153,462, filed July 14, 1937.

I claim:

1. A silencer comprising a chamber having inlet and outlet openings inopposite walls thereof, open-ended inlet and outlet conduits arranged injuxtaposed relation within said chamber, said inlet and outlet conduitsbeing connected at one end thereof to said inlet and outlet openingsrespectively and each extending from the wall opening to which it isconnected part way toward the opposite wall and having an open endlocated within said chamber, said inlet and outlet conduits havingopenings in the walls thereof and being arranged laterally adjacent oneanother throughout a portion of their length, the open ends of saidconduits located within said chamber being in free and unconfinedcommunication with each other through the space within said chamber.

2. A silencer comprising a chamber having inlet and outlet openings inopposite walls thereof, perforated open-ended inlet and outlet conduitsmounted in said inlet and outlet openings respectively, said inlet andoutlet conduits being chamber and each extending from the wall openingin which it is mounted into said chamber part way toward the oppositewall, said inlet and outlet conduits being arranged laterally adjacentone another throughout a portion of their length, the open ends of saidconduits located within said chamber being in free and unconfinedcommunication with each other through the space within said chamber.

3. The silencer of claim 1 in which the chamber is substantiallycylindrical and one of the inlet and outlet conduits is of annular shapeand comprises the interior space contiguous to the cylindrical chamberwall, and the chamber opening connected to said annular conduit is alsoof annular shape.

4. The silencer of claim 1 in which the openings in the walls of saidconduits occupy about 0.01% to 10% of the total area of the walls ofsaid conduits.

5. A silencer comprising a substantially imperforate casing having inletand outlet openings therein, at least one transverse partition withinsaid casing providing a chamber within said casing, perforatedopen-ended inlet and outlet tubes mounted in opposite walls of saidchamber and communicating with said inlet and outlet openingsrespectively, said tubes being offset laterally with respect to eachother and each extending fromthe wall in which it is mounted into saidchamber partway toward the opposite wall of said chamber and ending inadjacent spaced relation to said opposite wall, said oppositelyextending tubes being arranged laterally adjacent one another throughouta portion of their length and being directly exposed to one another, theopen end of said tubes located within said chamber being in free andunconfined communication saidwith each other through the space withinsaid chamber.

6. The silencer of claim 5 in which at least one chamber wall has aplurality of openings therein and a perforated tube is mounted in eachof said openings and extends toward but stops short of the oppositechamber wall.

'7. The silencer of claim 5 in which at least one chamber wall has aplurality of openings therein and a perforated tube is mounted in eachof said openings and extends toward but stops. short of the oppositechamber wall and the adjacent portions of the perforated tubes-extendingfrom opposite chamber walls are united mechanically.

8. The silencer of claim 9 in which the first partition has a pluralityof openings therein offset laterally with respect to the opening in thefirst end wall, and a perforated tube is mounted in each of said firstpartition openings and extends toward but stops short of the secondpartition.

9. A silencer comprising a substantially imperforate casing having inletand outlet openings in opposite end walls thereof respectively,substantially imperforate transverse partitions with in said casing andin spaced relation to each other, the first of said partitions being inadjacent spaced relation to the first of said end walls and having atleast one opening therein offset latorally with respect to the openingin said first end wall, a perforated open-ended tube mounted in saidfirst partition opening and extending part way toward the second of saidpartitions said second partition having an opening therein in alignmentwith the opening in said second casing end wall and offset laterallywith respect to said perforated tube, a second perforated tube mountedin the opening in said second end wall and extending through said secondpartition and part way toward said first partition and ending inadjacent, spaced'relation to said first partition, said perforated tubesbeing arranged laterally adjacent each other for a portion of theirlengths between said partitions.

10. The silencer of claim 9 in which the first end wall is the inlet endwall.

11. A silencer comprising an imperforate casing having inlet and outletopenings in opposite end walls thereof respectively and having aplurality of spaced apart, substantially. imperforate transversepartitions subdividing the interior thereof into a plurality ofchambers, the first of said partitions being spaced interiorly from thefirst of said end walls and having an opening therein offset laterallywith respect to said opening in said first end wall, a tube mounted insaid first partition opening and extending toward but stopping short ofthe second of said partitions, said second partition and the remainderof said partitions having openings therein aligned with each other andwith said opening in the second end.

wall, said aligned openings being offset with respect to said tube, asecond tube connected to said outlet opening and extending through saidaligned openings in said partitions and toward, but stopping short ofsaid first partition, said tubes being arranged laterally adjacent eachother for a portion of their lengths between said first and secondpartitions and being perforated at their laterally adjacent portions,said second tube having openings in the walls thereof communicating withthose of said chambers through which it passes.

12. The silencer of claim 11 in which one or more of the chambersthrough which said second tube passes contains porous sound-absorbingand gas-pressure-absorbing material.

13. The silencer of claim 11 in which the open ings of the perforatedportions of the tubes occupy about 0.01% to 10% of the area of the wallsof said portions.

14. A silencer comprising a substantially imperforate casing havinginlet and outlet openings in opposite end walls thereof respectively,substantially imperforate transverse bulkheads within said casing and inadjacent spaced relation to said end walls respectively, said bulkheadseach having an opening therein ofiset laterally with respect to theopening in the adjacent end wall, said openings in said bulkheads alsobeing ofiset laterally with respect to each other, and perforated tubesmounted in the openings in said bulkheads respectively and extendingpart way toward the opposite bulkheads and ending in spaced relation tosaid bulkheads, said tubes being arranged laterally adJacent each otherfor a por- 7 tion of their lengths.

' 15. A silencer comprising a substantially imperforate casing havinginlet and outlet openings in opposite end walls thereof respectively andhaving a transverse partition therein dividing the said easing into twochambers, open-ended inlet and outlet tubes connected to said inlet andoutlet openings respectively and extending part way toward saidpartition and ending in adjacent spaced relation to said partition, saidpartition having a plurality of openings therein, an openendedintermediate tube extending through each of said openings and part waytoward both end walls of said casing and ending in spaced relation tosaid end walls, said intermediate tubes being displaced laterally withrespect to said inlet and outlet tubes and being arranged laterallyadjacent said inlet and outlet tubes for a substantial portion 01' theirlength, said inlet and outlet and intermediate tubes having openings inthe walls thereof.

WILLIS LJMANNING.

